Byzantine agreement, the positive form of CERT-06: under honest non-equivocation and the Byzantine-weight bound, every pair of valid threshold certificates for a snapshot carries the same value. There is no fork at the certificate level.
The shared end-to-end safety conclusion: no conflicting leader ratifications, prefix-comparable outputs below a common limit, and parent closure preserved by receive-path insertion.
Equations
- One or more equations did not get rendered due to their size.
Instances For
The assumptions shared by the end-to-end safety variants. The ordering-specific assumption is kept separate, since each theorem discharges it from a different source.
- wf : S.WF
- byz_bound : S.ByzBound honest
- honest_non_equivocation (p : P) : p ∈ honest → ∀ (b b' : Block P Wave Slot Hash), BlockApproves L p b → BlockApproves L p b' → b = b'
Instances For
End-to-end safety (Theorem 4.54 core). Under the standard assumptions the protocol guarantees, in
one statement:
(1) leader-agreement: no two valid ratification certificates ratify conflicting target blocks;
(2) output consistency: correct miners whose blocklaces sit inside a common limit produce
prefix-comparable orders, so they never publish a conflicting position;
(3) blocklace integrity: dissemination's receive-path preserves parent closure.
The ordering's prefix-monotonicity (leader safety) enters as the hypothesis hmono, matching the
blueprint's leader-safety trusted boundary.
The concrete deterministic ordering is a valid total order of its input: it is duplicate-free, topologically sorted (no dependency after its dependent), and (under the strict-rank acyclicity hypothesis) enumerates exactly the input vertices. With determinism (topoSort is a function), the deterministic-ordering requirement is met by a real, computable algorithm.
End-to-end safety with the ordering hypothesis discharged. Same guarantee as end_to_end_safety_of_output_monotone, but for the concrete anchored ordering and assuming only the primitive leader-safety fact: the finalized-anchor sequence is prefix-monotone in the blocklace. Output-prefix monotonicity (TAU-08) is now derived (tau_08_anchored_output_monotone), not assumed, so the only ordering input is AnchorPrefixMonotone, which is much closer to the protocol than abstract OutputMonotone.
The deepest form: end-to-end safety with a fully concrete ordering and the ordering hypothesis
reduced to one scalar fact. The ordering is the anchored order over the finalized-anchor sequence,
and the only ordering input is that the finalized-wave count finalCount is monotone in the
blocklace (finality permanence plus wave-ordered finalization). Anchor prefix-monotonicity and
output-prefix monotonicity are both derived.
The final form: PoR-weighted Cordial Miners is safe, resting on three named facts. Given the Byzantine-weight bound (hByz), honest non-equivocation (hNoEquiv), and finality permanence (hperm: a finalized wave stays finalized as the blocklace grows), the protocol guarantees leader-agreement, output consistency, and blocklace integrity, for the fully concrete finalized-anchor ordering. The bound monotonicity (hbound) is a technical artifact satisfied by the block count. Every other ordering property (the finalized-wave count's monotonicity, anchor prefix-monotonicity, and output-prefix monotonicity) is derived.